Climatic change presents particular threats to alpine plants not least if the consequential effects of increased temperatures are the upward movement of plant species to increasingly higher elevations where they are available, ultimately leaving them nowhere else to go. Such movement has been documented in the European Alps, causing considerable concern as to the likelihood of alpine plant species extinctions. In many situations though, responses of species to changing climates in alpine regions are not so clear-cut. The involvement of other factors such as physiographic variation, changes in precipitation and wind regimes, encroachment by subalpine species, shifts in plant-animal interactions, and altered frequencies of extreme environmental events clearly point towards more complex and subtle changes in species distributions and abundance. Further, differential geographic effects on seasonal extremes and predictability of climatic conditions may select for particular functional traits. Continental alpine systems are characterized by short growing seasons and harsh winters, with many species displaying physiological mechanisms adapted to this climatic predictability. In contrast, species in oceanic alpine systems need to be able to tolerate and survive unpredictable swings in temperature, diurnally as well as seasonally.
Results/Conclusions
We suggest that climatic unpredictability over a range of temporal scales in oceanic systems, and in tropical high mountains too which are their ecological analogues, may have selected for species better equipped to cope with projected climatic change compared to those that have evolved in more extreme, yet predictable conditions. We use oceanic alpine New Zealand as a case study. Here, ground frosts and snowfalls can occur at any time of the year, and surface temperatures can reach 40°C in summer. Under such conditions, species arguably would benefit from being opportunistic, resilient and responsive over temporal scales from hours to lifetimes. We propose that an investigation which covers the gradient of oceanicity and its influence on fitness in terms of environmental resilience may provide insights into understanding how to protect alpine systems in a changing climate.